Back in September, a bipartisan immigration deal seemed possible if Democrats backing permanent legal status for the so-called Dreamers overcame their reservations and accepted President Donald Trump’s proposal to spend billions on a wall protecting the U.S. Southern border.

Over the ensuing five months, Democrats reluctantly agreed. But the president never took yes for an answer, each time upping the ante. By the time senators finally considered the complex issue last week, Trump had stiffened his terms to require dramatically stricter limits on legal immigration. When a bipartisan group floated a plan that held promise of attracting the required 60 votes, Trump and his team sabotaged its prospects, calling it a “total catastrophe” that would make matters worse.

The Senate’s latest display of congressional ineptitude has provoked the usual partisan recriminations. Rival factions finger Republicans for demanding too many immigration curbs and Democrats for resisting them. But on this one, as a detailed Washington Post account made evident, one person bore the primary responsibility: President Donald Trump.

As Harry Truman said: “The Buck Stops” on the president’s desk.

Despite Trump’s repeated promises to provide relief for up to 1.8 million illegal immigrants covered by the Obama-era Deferred Action for Childhood Arrivals program, he prefers using immigration as a political issue. Presumably, it’s how he hopes to rouse the political base, as it may be his only hope of preventing a Democratic tide next November from capturing the House and unleashing its investigative arms (and possible impeachment) against his administration.

Logic would suggest that enacting a bipartisan bill would enable Trump to claim two victories. He could say he had achieved the wall he portrayed in 2016 as a panacea for illegal immigration and he had protected the mainly Hispanic Dreamers.

But Trump has never been interested in either logic or broadening his base, especially to Hispanics. Politics grown gridlocked and partisan require flexibility, but his steadily stiffening conditions may have been the most cynical excuse for inaction so far. (It’s perhaps rivaled only by Speaker Paul Ryan’s suggestion that more study is needed on the easy access to the high-powered military-style weapons used in recent mass murders.)

On both issues, public sentiment overwhelmingly favors action, to protect the Dreamers and to tighten restrictions on availability of certain weapons. It’s not even close. But the most rabid opponents are hard-core Republican conservatives, and the GOP needs their enthusiasm and votes to counter a likely mid-term reaction against the incumbent president.

Judging from their reactions, Trump seems to have cowed most Republican legislators into providing reflexive support reminiscent of the old Soviet Politburo. But blame for this fiasco needs to be shared with his two co-conspirators, Senate Majority Leader Mitch McConnell and Speaker Ryan.

McConnell kept his promise to the Democrats to put the immigration issue on the Senate floor without pre-conditions. But he managed the debate in a way that made it harder for a potential bipartisan consensus to emerge. It makes a journalist who covered the Senate in the 1960s and 1970s wonder whatever happened to the traditional legislative procedure in which committees considered bills, brought them to the floor and then opened them up for senators to offer amendments.

Through his actions, McConnell made it quite clear his preference was to prevent, rather than facilitate, passage of the legislation. His main goal: to make life harder for Democratic senators running for re-election in conservative states Trump carried in 2016.

Of course, failing to help the Dreamers may make it harder for Republicans to hold seats in Arizona and Nevada, the two likeliest places for Democratic Senate gains. And failing the Dreamers could damage the party’s long-term future, the way former Gov. Pete’s Wilson’s anti-immigration policies did two decades ago in California.

The situation in the House won’t require overt sabotage from Trump. By his continuing blind adherence to the Hastert Rule, which limits floor consideration to measures backed by a majority of Republicans, Ryan ensures no bipartisan legislation passes.

After last week’s impasse, McConnell shelved the issue and the Senate took off for a week. But some supporters of the Dreamers note there’s time to resolve matters, thanks to two court decisions temporarily blocking the administration’s September decision to terminate DACA on March 5.

One possibility would include a DACA fix and funds for the wall in the big funding bill lawmakers must pass next month. The irony is that could have been done in the first place, had Trump not played politics rather than seek a solution.